Want Gentoo *and* XP? Tip: Use A Second Drive!

[sundialsvc4]

Lots of folks want to try Linux, Gentoo or otherwise, while keeping the ... (ugh!) ... Windows-XP system that they still depend-on safely out of harm's way.

How to do that easily? Here's my suggestion: buy and install a second hard-drive. Or maybe two of them. You might have a drive, of recent vintage and good capacity, that's pure-and-simple a leftover, maybe in a computer that you no longer use.

Most computers have two built-in disk-controller chains on the motherboard, with the capacity of two drives apiece... total four. But there are usually only two devices: "the" hard-drive and a DVD/CD ROM. So this means that, with very little effort, you can install two more drives in the box. (And that's excluding USB/FireWire external drives, which can also be used for this purpose and for backups.) All you need is the drive(s), the cables, and probably an installation-kit containing screws and brackets. Read the directions carefully, and it takes about fifteen minutes to complete. Boot from a Linux LiveCD and partition the new drives for Linux.

Most computers can boot from any installed drive, or from USB/FireWire, or from the network. So, now you can install Gentoo (or whatever) onto "the other hard drive," leaving the Windows-XP installation completely alone. You make absolutely no changes to the drive upon which Windows-XP lives.

In the simplest scenario, you could select which OS to boot by altering the "setup" screen in your BIOS. (Some BIOSes have features specifically designed to let you store several "configurations," to achieve "dual booting in BIOS." Very handy if you have it.) Or, you could install Linux to the "other drive" and boot from that drive by default, setting up one of the GRUB menu options to boot Windows.

During startup, Windows (and Linux) will of course "see" that you have new drives, but it will also see that they are partitioned .. using a partition-type that it (probably) does not recognize. So Windows will leave those drives alone. Linux might see its partitions are mounted on devices such as /dev/hd"b,c, or d," rather than "hda," but that doesn't matter... just configure /etc/fstab appropriately when you install.

I personally have three drives in my main box, and I do this because having space, and drives, to spare gives you wonderful flexibility in doing things. Wanna try two Linux distributions? With two spare drives you're free to do so.

Notebook users (with a USB 2.0 or FireWire port) can do the same thing using external disk drives, as long as your hardware knows how to boot from them.

[dgaffuri]

Do you sell disks?
BTW, my laptop _won't_ boot from external drives.
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[Yuusou]

I would actually disagree with being able to boot from external drives (USB). I have seen maybe one computer with the ability to boot from those devices. A lot of BIOS's say they can, but don't seem to be able to anyways >_> And it's not the hardware that knows how to boot from external devices, it's technically software considering the BIOS is what manages that And I really don't see the point of ur post...o_o This forum is more for answering questions >_> And yeah...some of what you said isn't true so =\

[Earthwings]

My laptop boots from nearly anything, USB drives/sticks among them. I prefer isolating Windows in a file (qemu image) on an external USB drive though.

Moved from Installing Gentoo to Documentation, Tips & Tricks.
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[sundialsvc4]

Laptops ... ahem ... vary considerably. My "old Dobbin" is unfortunately dirt-on-wheels. But it's paid-for, and it does boot from a network, which is a good thing because right now the DVD drive is busted. Newer machines do have a lot more options, and one day I'm sure that ... *sniff!* ... Bang! ... I'll have to replace it. (But I'm so gosh-darned cheap.)

[Sheepdogj15]

why not get coLinux and create a Linux environment within a Windows environment? they even have a Gentoo tarball.

i must confess that i haven't tried this yet, as my main workstation is pure Gentoo Linux. However, i have Windows PC i'm turning into a backup server, and without getting too technical i need a few functions carried over from Linux. i may report back if i get it to work well.
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[sundialsvc4]

The answer is ... because this is simplest. It requires no configuration-changes whatsoever either to Windows or to Linux. Two entirely separate environments, stored on two entirely separate disk volumes, perhaps with a third volume as a spare for backups or as a dustbin. For sheer simplicity and reliability, I just don't think you can beat it.

[Sheepdogj15]

you are probably right. i'm not sure if the install process for colinux is more convoluted than for Gentoo (it is at least possible that this isn't the case), but it probably is.

on the other hand, the disadvantage of a dual boot system is that... it's a dual boot system. if you are in Windows and decide to go play with the penguin, reboot! when you are in Linux and realize your homework (which has to be submitted with Internet Explorer, grumble grumble) is due, reboot.

having access to one environment while in the other gets around this annoyance. this is especially good for n00blets: i learned Linux on a second computer, because before i had access to a WM or was savvy with lynx, i relied on Windows to search for docs, seek support, etc. then you have some apps you'd rather run in Linux but have others that can only be used in Windows. again the dual boot model suffers.

there is always going to be a tradeoff. heck, i think the two computer model with a KVM switch or a remote desktop application would be ideal, but some people may not find a second computer in their budget. space limitations would also be a factor. the dual boot model (heck, you don't even have to have two drives, just at least two partitions) seems to cut the middle... not the most convenient, but not the most costly either.
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[albanard]

Hey Sundial,

Thanks for your post. I've been looking for a while for a bios that can support dual boot. Mainly because I don't want one operating system to see (or touch!) the other at all. I.e. If bios can be setup to completely disable one disk and boot from the other or visa versa via a menu, that would be exactly what I want. It seems that this would be achievable with what you found. Where did you find such a BIOS? DO you know of any laptops that have a bios like that? (Some laptops are shipping with dual hard disks these days).

Also with the grub method (i.e. set bios to boot into linux HD then use grub to select windows) is it possible to make linux invisible to windows after this or will windows still see linux?

Does anyone know if there are any bios' capable of booting into / disabling partitions rather than disks. I'm not talking about helper programs that have their records in MBR etc, just at a bios level.

Cheers

Al

[Sheepdogj15]

you don't need a whole BIOS, as you can just configure Grub to give you that menu. it's just a matter of what's in your master boot record. i think the example in the gentoo installation handbook shows a dual boot config with Gentoo and Windows, you just have to know which partition/drive each is on.
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[DagonSphere]

And, if you have a second disk, you can make your Linux the master and the Windows the slave. This way, you don't touch the boot loader that Windoze installs. Here's an example of the windows portion of the grub.conf for windoze installed on the first partition of the second drive

title = Windows 98
root = (hd1,0)
map (hd0) (hd1)
map (hd1) (hd0)
makeactive
chainloader +1

The 'map' command tricks windows into thinking that it's really on the first ( C: ) drive. Otherwise, things go very wrong!

And, should you decide you don't want linux, you can go back to the original untouched drive. Of course, who would really want to do that????

[CHAOSACES]

I prefer to keep my os'es (Gentoo and Windows XP) and frequently accessed data on my first drive, and swap, page, and backup partitions on my second (on a separate IDE channel for performance.)

[albanard]

Thanks for the replies, I guess I should explain myself a little better. Some years ago I attempted the mission of having windows and linux installed on the same hard disk and went through many painful and agonizing episodes of windows overwriting my mbr and basically giving little warning or information that it was going to do so (in fact no warning as I recall), with many other problems occuring as a consequence. I don't remember the exact circumstances, but I do remember that I made a solemn vow never to trust windows with my other partitions / drives again. Thats something that aint gonna change.

So I know its possible to have a bootloader in the MBR that selects a partition to boot from, but my real question is how can windows be fundamentally prevented from seeing the other hard disk / partition. I.e. Once Windows loaded, there would be no way for it to activate / view another partition or disk. The only way I can see for this to happen is to have the operating systems on separate disks and use the bios to select which one to start while disabling the other.

I don't know much about the map command, thanks dagonsphere I'll look into that. The "Otherwise, things go very wrong!" bit is a bit scary though . I'm actually looking into vmwares new "free" offerings but I'm not sure where that will lead. Might work well with the new dual core processors. I don't mind lugging 2 hard disks around for piece of mind though.

Another prob with a bootloader is if I stick the latest version of windows on cd-rom in (e.g. to upgrade or reinstall the OS) and boot the computer, I guess the system won't even look at the mbr of the hard disk, just the cd-rom. So I would again be at the mercy of windows. If anyone knows any other ways to isolate windows I'm all ears.

Al

[huh_dude]

This has been covered before. In brief: the Window's mbr doesn't get touched as the Grub bootloader is small enough to live underneath microsoft's waters and come up gasping for air before Windows knows something bootloader'ish is active in a non-Windows partition. To Dual boot, Grub's partition must live on the active boot device, ie. the Linux disk. You simply set the Bios to look at the Linux drive at boot. Grub's dualboot configuration sends the system scurrying over to the Windows drive and the Windows bootloader takes over from there.

Grub's boot partition and installation setup loads the bootup OS selection it was configured to do and then Grub goes back to sleep. Windows never knows it has been legged up. Windows doesn't see a foreign Filesystem partition format. It will not see the other drive.

I wonder if USB memory sticks are the new stealth net candidate?
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#include <milk>
#include <iomanip>
int main()
{
const float large_mug=pourPot;
cin>> coffee | large_mug;
cout<<"Coffee"=coffee;
}
#make Coffee ..was zero, the program wouldn't work.

[albanard]

Thanks dude,

That does seem like it would be secure enough, with a 2 disk setup. Hmm interesting. I guess then if I wanted to reinstall / upgrade windows I could simply unplug the linux drive for a bit (ensuring its protection) and then install windows with its own mbr etc on the windows drive. This is sounding pretty good! (Its probably what dagonsphere was getting at too). Do you remember where this was covered, with the 2 drive grub conf, or would it simply be the conf that dagonsphere posted above?

Al

[pste]

Stumbled into this... don't know if I'm bringing something new to the table, but anyway...

I've successfully dualbooted xp and different flavours of linux for a couple of years using grub and my experiences could be summarized to this:

#1
Arrange for having a small primary (2GB was the smallest possible on my newest system) partition (or empty space) at the beginning of the drive. This is going to be the /boot partition and the place for the grub install.

#1a - you haven't installed xp yet!
To fool xp, either use a linux fdisk program and format the space with ext2 or use for instance powerquest partitionmagic to hide the partition (I can't remeber if MS fdisk is able to hide partitions, but I actually think that I've used it to do that... Hmmm, isn't it so that if you select a partition other than the first one as the only bootable one, then the ones in front beomes hidden???). Anyway, with this setup xp installs as if it's the only thing on the drive, getting the %system-root% to C:

#1b - you already have xp installed and don't want to reinstall it from scratch... (kind of an unpleasant work...)
Well, this is the tricky part, isn't it. Either you have a program like partitionmagic and just resize and move the xp partition (but make sure to backup all important data, partitionmagic do mess up things time to time..) or you need to find another workaround. If you have xp installed on a single partition of the entire drive I personally don't see another solution that partitionmagic (or similar...). If the xp partition is smaller than the drive you have another option. Once I've managed to make an image of the xp partition (to another drive), repartioned the drive according to #1(a) and restored the image...

#2
Install Linux (preferrably Gentoo ) on a partition of choice. And install grub and select to install the boot loader in the MBR.

Result:
With this setup I've never needed any map trick in grub and xp doesn't mind - it works as intended.
XP has never messed with the setup.
I have no restrictions in partitioning scheme after this, free of choice for both windows and linux partitions but I ususllay end up with something like this (on a single large drive system):

h(s)da1 - boot/grub
h(s)da2 - xp system
h(s)da3 - gentoo root
(h(s)da4 - extended partition)
h(s)da5 - ntfs work
h(s)da6 - gentoo /home
h(s)da7 - fat32 (for being rw accessible from both systems)
h(s)da8 - linux swap

However I strongly agree with sundialsvc4, buy more drives, they are cheap nowadays and spread the partitions (for ex. swap as a primary part. on another drive). But, partitioning strategies are another issue extensively discussed elsewhere...

Caveats:
When dealing with drives larger than 120GB - be careful. My experience is that it's easiest just to create the two first partitions (boot and xp) and together make them smaller than 120GB. Install xp - including sp2, create the rest of the partitions and then install your linux system.

Whatif:
Have a Gentoo live cd (installation cd) at hand (or similar). Then you're able to fire up fdisk and toggle of the bootable flag of the /boot partition making the system a xp only one. You're also able to get into your gentoo system and reinstall grub (and boot loader into the MBR) if something is messed up. And, you're able to edit the config files when something became wrong (which it always does...)

Summary:
I wrote this because I think the map trick is unnecessary (and I believe you should minimize the use of tricks...) and I hope someone can use some of the information and that something wasn't already written in this trail
Just FYI, my grub.conf lookes like this, note the straightforward windows boot entry... (and yes, I have more than one harddrive ).

[albanard]

Thanks for all the tips pste.

Let me see if my logic is right on this. I'm thinking the boot process is:

1. Switch on power
2. Computer searches for boot device, lets say its the one single HD
3. It reads the MBR of this drive (The MBR is always located right at the start of the drive, outside any partition right?)
4. The MBR tells it to go to the active partition (Lets say this is the small grub partition at the start of the HD)
5. Grub loads, then in grub you can choose to either boot into the windows or linux partition
-> If you boot into windows then it won't see any partitions formatted as ext3 etc., so that effectively hides those partitions from windows
-> If you boot into linux then you can see all partitions provided you have supprt compiled in, but thats ok.

The only problem I can see with this is that there is still no way to physically separate linux from windows. So if I put in the new windows 2010 edition CD in the future (ie. it would become the boot device), it might have a new user friendly feature that automatically takes care of all partitioning (and potentially formatting) for me, and subsequently erases all linux (perhaps seen as empty or corupt because they can't be read) partitions from the partition table and whacks on its own MBR. Does anyone know if it did do this, and change the partition table in the MBR, does that corrupt the exisitng partitions, or would it simply be a matter of reinstalling a backed up MBR? I think its much less likely that it would format a partition without asking, so if I stopped it in time then that might save the partitions. Still I think keeping the OSs on different disks seems more comforting to me, its just not as practical for say a laptop situation.

Another question, if I had my linux swap on the second drive (the one with windows) for performance reasons and it was deleted or the second drive failed, would it still be possible to boot into linux with no swap partition (as all the space might be used up by exisiting partitions on the linux drive, so creating a new one would be hard without loosing data)? It might be worth reserving say a GB at the end of my linux drive for an emergency swap incase this happened, and just use it to dump temp data during normal operation.

[pste]

Well albanard,

As far as I understand you're quite correct. However, WindowsXP do see the linux partitions but marks them as of unknown type and disregards them (they dosen't interfere with drive letters and so on). When it comes to your new windows 2010 scenario I definately think you've got a point. Still, before installing a new wonder os from MS I definately would backup all my work and knowledge that I've put into a nice and well working Linux system. Which leads to two considerations.
#1: always write down all gotchas and out of hard work discovered solutions to problems you have during system setup -> if the ever worst thing would happen, either because of a harddrive failure or a MS system playing monopoly, than it will be a simple thing to reinstall your linux system. I mean that's one of the nice things about Linux, if something works once it will work the next time as well .
#2: In the year of 2010, hopefully you won't need to install anyting from MS...

OK, trying to be serious. If you use a partioning program and unset the bootable flag, or even if possible hide the grub partion, I believe you have quite good odds even when installing a MS system alongside (although you need to be careful when you answer all the questions...). Some MS repair functions do write a "fresh" MBR, which is possible to restore from grub (via either a live cd or something similar).

About swap space: You don't have to have a swap space! And if your swap partition is hijacked you either only have an error message during boot or you'll have to edit your /etc/fstab file (via a live cd or similar, again...) and comment out your swap partition.

Did this answer your questions?

/pste

[albanard]

Thanks pste ,

I think that pretty much covers it.

[DagonSphere]

albanard ~~

You did pick up on my train of thought. My thinking is, when installing Windows 98/NT/2000/2010, install it on its own dedicated drive, with ALL Linux disks unplugged. This lets Windows have full reign over the entire system to do with as it pleases during installation. When the install is done, plug all the drives in the way they were (with grub on hda1, or however you had it), modify your grub.conf file for the MS OS, install it, and you're good to go.

I prefer letting MS install on its own disk. This way, you can swap drives to make your MS drive hda, and it has its own boot loader -- In case grub gets hosed. And, I could be mistaken, but I believe that Windows will only install on the the first drive, and (this is where I'm fuzzy) on the first partition.

Yes, the MBR is outside the standard partition space.

And when the install is complete, I'm not sure there's a way to prevent Windows from 'seeing' the Linux drives. They show up in the device manager, or whatever. But there's nothing preventing a user booted up in Windows from destroying your Linux disks/partitions. They can't read it, but they can format them

HTH!!

[irondog]

[DagonSphere]

Interesting. I never knew that. So, does grub and lilo act the same way, ie, installing a 'pointer' on the MBR, or does it fit in its entirety in the MBR?

[albanard]

[DagonSphere]

I think I found the answer. This is for GRUB v0.5.??. (Yes, I know it's old, but it's all I could find)

Here's the link to what I found http://www.faqs.org/docs/Linux-mini/Multiboot-with-GRUB.html

Here's a snippet of code for a Windows partition

[albanard]

Cool, looks interesting. I won't be trying it till I get a new computer, but I'm planning to do that in the next couple of months so this is definitely good info.